The Minerals Management Service (MMS) of the U.S. Department of the Interior (DOI) has federal responsibility for oil and gas development on the U.S. outer continental shelf (OCS). From 1954 through 1989, the last year for which statistics have been published, OCS oil and gas development provided almost 8% of total domestic oil production, about 14% of domestic natural gas (with higher percentages in recent years), and more than $93 billion in revenue from cash bonuses, lease rental payments, and royalties on produced oil and gas.
MMS's Environmental Studies Program (ESP) is responsible for the conduct of environmental studies on the OCS and for the collection of information to prepare environmental impact statements and to inform federal management decisions. The ESP (which began in 1973 under the Bureau of Land Management) through 1989 had invested more than $478 million in a wide variety of studies. Ecological studies have accounted for approximately 54% of the ESP budget, for a total expenditure through 1989 of over $259 million.
THE PRESENT STUDY
In 1986, MMS requested that the National Research Council (NRC) evaluate the adequacy and applicability of studies conducted in the ESP, review the general state of knowledge in the appropriate disciplines, and recommend future studies. Under the auspices of the NRC Board on Environmental Studies and Toxicology, the Committee to Review the Outer Continental Shelf Environmental Studies Program was formed to conduct the assignment. Three panels—dealing with ecology, physical oceanography, and socioeconomics—were established to review specific aspects of the assessment. The Ecology Panel investigated the main questions of ecological relevance to OCS oil and gas activities and ecological aspects of the ESP. This report, the second in a series, presents the findings and recommendations of the Ecology Panel.
The panel based its report on several sources, including presentations from ESP staff; briefings by other, independent scientists familiar with the work supported by the ESP; results of workshops on ecological studies held by the panel; and a review of relevant scientific literature and documentation of MMS's planning and implementation process leading to various lease sales. While this report was being prepared, the OCS committee and its panels interrupted their work to prepare two reports on the adequacy of environmental information for OCS decisions in response to government requests. The first, requested by President Bush, dealt with a lease sale off Florida and two off California and was published in 1989. The second, requested by MMS, focused on a north Atlantic lease sale and was published in 1991.
For this report, the panel reviewed documents that were available through 1990. MMS has informed the panel that the ESP continues to evolve, and recent MMS requests for proposals confirm that. MMS officials have also indicated that they are taking into account recommendations in the two recent reports mentioned above.
The Ecology Panel was divided into three working groups: on marine birds, mammals, turtles, and endangered species; on benthic processes; and on fisheries and ecosystems. The panel conducted workshops on each of those topics, focused on the progress of the ESP in assessing the environmental impacts of OCS oil and gas activities, evaluated shortcomings of the ESP, and identified future information needs.
The biological characteristics of the components of marine ecosystems dictated the types of information gathered for evaluation by the ESP and therefore the nature of the panel's review. OCS activities can have ecological effects during exploration, development, production, and decommissioning. The potential ecological effects during each phase are distinct and require a different suite of studies for prediction of their extent and duration. The panel identified six objectives of obtaining information for assessing the environmental impacts of OCS oil and gas activities:
Characterization of major habitat types.
Identification of representative species (or major species groups) in the area of interest.
Description of seasonal patterns of distribution and abundance of representative species (e.g., identification of spawning and feeding grounds).
Acquisition of basic ecological information on key or representative species (e.g., trophic relationships, habitat requirements, and reproduction).
Determination of basic information on factors that determine the likelihood that various populations and communities would be affected by OCS activities, and the potential for recovery.
Determination of potential effects of various agents of impact (e.g., spilled oil, operation discharges, noise, and other disturbances).
Information for the first three objectives is needed before leasing; more site-specific information for the second three is needed after leasing (during exploration, development, and production). All six objectives were kept in mind in the review of various components of the ESP and the preparation of recommendations for future studies.
MARINE BIRDS, MAMMALS, AND TURTLES
A major goal of many studies in the ESP has been to provide an inventory of the seasonal distribution and abundance of species in each OCS area. That information is necessary for describing the biological resources present, identifying places and times when populations are especially vulnerable to local impacts. Ideally, such early studies would lead to monitoring of selected sites so that natural rates of change and processes could be identified before oil is produced. In most instances, the panel found that this information provided a valuable assessment of the resources present.
The ESP has provided a major impetus for the study of marine birds and mammals in the coastal waters of the United States. Through those studies, knowledge of the distribution and abundance of breeding North American seabirds, the pelagic biology of seabirds in U.S.
waters, and the distribution and abundance of marine mammals (especially cetaceans) has increased dramatically. The distribution and abundance of sea turtles in OCS areas (especially in the Gulf of Mexico) have received much less attention. There have been relatively few detailed studies of the responses of populations of marine birds and mammals to environmental impacts of different OCS activities (e.g., responses to oil spills and noise impacts on cetaceans) or environmental change. Further investigations are needed to increase understanding of the vulnerability of specific populations to impacts of OCS activities and their ability to recover from them.
One of the major achievements of the ESP is the characterization of benthic habitats of the U.S. OCS, including analysis of benthic fauna and physical and chemical characteristics. The dominant features and processes of OCS areas are adequately described to support more detailed site-specific studies on processes that govern shelf environments and evaluation of the impacts of environmental perturbations. In most instances, however, understanding of spatial and temporal variability in continental shelf habitats is limited, and there is little understanding of the relative vulnerability of the habitats to environmental impacts of OCS oil and gas activities. Studies have been conducted primarily in frontier areas of the OCS, and there has been little postexploration study of effects. Future research should continue to move toward gaining a better understanding of benthic processes that influence the fate, transport, and effects of OCS operational discharges and understanding of the impacts of other OCS-related disturbances, including those in nearshore and onshore habitats.
FISHERIES AND ECOSYSTEMS
Qualitative assessment of the responses of fishery resources to environmental impacts of OCS activities have received little attention from the ESP except in the Alaska OCS region. Studies have been directed mainly at understanding the response of early life-history stages (i.e., eggs and larvae) to oil spills (through experimental and modeling approaches), sublethal effects of petroleum hydrocarbons on fishery resources, and habitat and distribution. There have been relatively few quantitative assessments of the effects of OCS oil and gas activities on fishery resources.
Mathematical models of fisheries and ecosystems should play an important role in assessing the effects of OCS activity, although they must be used with caution. Models have been developed to assess the acute effects of oil spills on resource species, but many models require better integration with observational data. Models of the fate and effects of chronic discharges require further development.
The Minerals Management Service's mandate to assess potential impacts of OCS activities, as specified in the OCS Lands Act as amended in 1978 and in other authorities, although reasonable from the viewpoint of public policy, required the acquisition of information and the development of predictions that could not be accomplished with the available time,
resources, and scientific expertise. Therefore, MMS has allocated its resources to studies that support specific lease sales at the expense of longer-term studies that would have provided a better scientific basis for prediction and assessment of impacts of OCS activities.
In general, with a few exceptions, the panel found that the information available on inventories and distribution of marine birds and mammals and the characterization of benthic environments were adequate to define the resources at risk from OCS activities. The principal exception to that finding is the lack of information for OCS areas in the Gulf of Mexico, specifically on the at-sea distribution of birds and mammals, the distribution and abundance of sea turtles, and characterization of benthic communities sufficiently detailed to support leasing decisions. In addition, data on seasonal and yearly variation of many ecological variables of OCS areas are lacking.
There has been a lack of ecological process-oriented programs for many regions of the OCS, studies that would yield information on ecological processes, population dynamics of significant species, and interactions between physical and chemical processes and biological communities. Such information is needed to support assessments of the sensitivity and vulnerability of biological communities to OCS-related activities, and it can also provide a basis for developing strategies for reducing impacts and mitigating them. Studies linking an understanding of physical and chemical processes, of their effects on biological communities, and of the fate and transport of OCS-related discharges are critical during all phases of OCS oil and gas activities. Those studies should assess not only the short-term effects of exploratory drilling on the OCS, but also the long-term effects of chronic discharges during development and production. The latter point was recommended in an earlier review of the OCS oil and gas program.
Within the ESP, there has been a lack of focus on the impacts of OCS activities on nearshore and onshore communities that, although unlikely to be affected during exploration, could be seriously affected when shore-based facilities are constructed or spilled oil moves ashore. Concern for nearshore and onshore communities was highlighted in earlier studies, especially regarding areas where critical habitats of endangered or threatened species could be affected (e.g., the Gulf of Mexico).
MMS's environmental impact analyses to date have emphasized the potential impacts of spilled oil. More attention needs to be given to other potential impacts of OCS development and production, including those associated with the discharge of drilling fluids, produced waters, spill dispersants, and other chronic discharges, in addition to ship and aircraft traffic, onshore development, pipeline construction, removal of facilities and possible cumulative effects of petroleum-related industrialization on organisms and their habitats.
Regional programs within the ESP vary from one region to another in the scientific quality of completed studies, the integration of data from different disciplines, and the acquisition of critical information. The variation was also recognized by the NRC's Physical Oceanography Panel in its review of the ESP. MMS should sharpen its focus on specific scientific hypotheses in developing its strategies for the acquisition of ecological information that can be incorporated into regional study plans. Strengthening the scientific bases of its strategies would result in less-fragmented studies that are better integrated across disciplines and regions and more closely fulfill the mandate for assessing the impacts of OCS oil and gas activities.
Although some extensive data sets have been acquired (especially resource inventories), MMS has not yet established a data management system that will allow it to determine effectively where its effort has been expended or where biological resources are. The panel understands that MMS is again working on the development of a computerized data management system that is intended to permit retrieval of data on study effort, as well as on the
distribution and abundance of organisms. While MMS has recently made an effort to have the results of ESP research published in the peer-reviewed literature, many of the earlier studies were not treated in this way.
The panel offers six general recommendations for future ESP ecological studies.
The ESP should support more ecological process-oriented studies and studies of ecological relationships designed to predict environmental impacts of OCS oil and gas activities.
A major achievement of the ESP was the characterization of benthic habitats and the distribution of bird and marine mammal populations. Although identification of resources at risk and characterization of habitats will still be required in new frontier areas of the OCS, the need for only broad-scale survey work has passed. Future research should focus on process-oriented programs designed to evaluate mechanisms that control the distribution of populations and communities, such as trophic links between benthic habitats and pelagic communities. The research should focus on the appropriate temporal and spatial scales. For example, the processes by which and the rates at which populations recover from disturbance must be understood in all habitats affected by OCS-related activities. In addition, there is a critical lack of understanding of the proper temporal and spatial scales for evaluating OCS-related impacts, especially on benthic areas. Existing data (data from MMS, data on fisheries, and any other available data) should be analyzed and used to discern proper scales for future research. It is critical to use information gained from studying OCS impacts and attempts to mitigate them in planning future activities. In other words, OCS activities should be treated as scientific experiments whenever possible.
MMS, through the National Oceanic and Atmospheric Administration's Outer Continental Shelf Environmental Assessment Program (NOAA/OCSEAP), supported the development of analytical chemical techniques for determining concentrations of hydrocarbons and biochemical techniques for examining sublethal effects of hydrocarbon contaminants, metabolites, and reaction products. Advances in methodology have progressed in the scientific community at large with funding from various sources. These techniques have improved understanding of the fate and effects of hydrocarbon contaminants in the marine environment. MMS should incorporate them into future study plans to improve understanding of the biogeochemistry of hydrocarbons that might affect benthic ecosystems.
The vulnerability of different shelf habitats to discharges from OCS oil and gas activities and the mechanisms that control recovery are not well understood. MMS should continue to direct its efforts toward a greater understanding of the mechanisms involved in habitat restoration and recovery.
For birds, MMS should promote studies of processes responsible for foraging aggregations, both near and away from breeding colonies, and integrate them with work in other specific disciplines (physical and biological oceanography, fisheries, etc.). MMS should cooperate with other organizations to take advantage of and help support current long-term studies of reproductive ecology that are developing data on population and community processes. MMS should conduct additional surveys of migratory routes to identify areas of concentration and their timing. For marine mammals, MMS should ensure that the emphasis of
studies on high-profile species is not at the expense of others, less visible, that may be more sensitive or vulnerable.
OCS oil and gas activities constitute only a portion of all human activities in the coastal and continental shelf areas (e.g., commercial fishing, shipping, sewage discharge, etc.) that can have adverse impacts on ecosystems and living resources. Thus, an understanding of the interactions of OCS activities and other disturbances is needed for an assessment of absolute and relative environmental impacts of OCS oil and gas activities.
In addition, OCS oil and gas development could have serious immediate and chronic long-term effects on intertidal and nearshore habitats. Because of their popular appeal and exposure to waterborne oil and debris, the narrow intertidal habitats are among the most valuable, yet vulnerable, marine habitats in the world. Although these fragile habitats and ecosystems are inshore of the legal OCS limits, they are vulnerable to the effects of OCS oil exploration and development and must be better represented in MMS's studies.
More emphasis is needed on long-term and postlease studies that are directed toward a better understanding of the environmental impacts of OCS development and production.
Until recently, ESP studies have focused on preleasing activities, primarily in frontier regions of the OCS, and not on the effects of exploration, development, and production. Almost all the natural patterns represent time scales that must be evaluated in terms of decades, rather than years; and it is absolutely critical that long-term (multiyear) postlease studies be established. Postlease research involving exploration, development, and production must include long-term programs that can discriminate between natural changes and OCS-related changes and can discern interactions of OCS activities with other human activities in specific regions. Long-term studies, including time-series analysis (such as those conducted in the California Cooperative Fisheries Investigation), should define the spatial and temporal extent of the impacts of OCS activities. For birds, MMS should establish a subset of potentially vulnerable colonies and should run a statistically based program to monitor numbers and reproductive biology of selected species during leasing, exploration, and production. Detailed long-term monitoring studies should also be done for selected species of marine mammals. The development of monitoring programs to verify predicted effects can be used to ensure that effects do not reach unacceptable levels. MMS should hold a workshop and collaborate with other agencies (e.g., Fish and Wildlife Service (FWS), National Marine Fisheries Service (NMFS), state agencies) to identify useful indicator species and to outline the types of long-term monitoring studies that could be done to verify the predicted effects, and detect the possible unforeseen effects of OCS activities in different regions.
One important component of postlease analysis is the understanding of the long-term effects of oil spills on both the OCS and nearshore habitats. Therefore, MMS should take advantage of accidental and experimental oil spills for research, to examine the persistence of hydrocarbons in the marine environment, to identify the processes related to the degradation of hydrocarbons, and to define the mechanisms that control the recovery of specific biological communities as it did recently with the Nestucca spill off the Washington coast. It is extremely important that the sites of large oil spills receive periodic restudy. MMS should hold a workshop, together with other agencies, to develop contingency plans for responding scientifically to different kinds of oil spills in different areas and to use them as a means for verifying otherwise unverifiable hypotheses concerning the effects of oil and marine living resources and the ecosystems of which they are a part. The data collected from many studies of
the Exxon Valdez oil spill were not available for review and incorporation into this report. When most of the data have been made public and peer-reviewed, we are likely to gain valuable insights about the fate and effects of spilled oil in subarctic environments.
Models are important for understanding ecosystem processes and environmental impacts of OCS activities. However, the development of models requires observational data for verification, and use of models does not replace the need for further work in the assessment of environmental impacts of OCS activities.
Modeling is an important tool that can provide insights into a variety of ecosystem processes and should be used not as a substitute for field programs, but in conjunction with field programs to identify specific information gaps. To improve predictive capability for ecosystem modeling, MMS should:
Use models to identify critical data gaps and processes that must be understood to predict accurately the possible environmental impacts of OCS activities.
Provide data on rates and processes for models.
Take advantage of theory and techniques that are being developed for constructing ecosystem models.
Take advantage of modeling expertise that exists outside of current MMS contractors.
In all cases, models should be tested against and calibrated with field observations before their outputs are used to assess and manage OCS environmental impact.
MMS needs a data management system that is accessible in a timely manner and allows the integration of information from different disciplines.
MMS has produced a large quantity of data—some interpreted, some not. Improvement is needed in MMS's data management, including synthesis, storage, and retrieval. MMS should continue to develop integrated data bases on biological resources potentially at risk. The data bases should be reproducible as maps. Formats should permit ready retrieval on a geographic basis. GIS systems could be developed and used to help organize and integrate multidisciplinary geographic data in each OCS region. MMS should continue to develop information exchanges with other agencies. In addition, MMS should continue to encourage the publication of study results in the peer-reviewed scientific literature. Final reports can be difficult to find, and they often are not critically reviewed or integrated for an understanding of broad-scale impacts of OCS-related activities when not published in peer-reviewed scientific literature.
MMS should sharpen its focus on the specific scientific hypotheses underlying its strategies for the acquisition of information so that the information can be incorporated into regional study plans, and should strive to integrate regional study plans across disciplines and regions.
MMS needs to develop study plans that include more hypothesis-testing and greater recognition of the spatial and temporal scales on which effects of specific OCS activities can occur.
MMS should help in the curatorship of the large collections obtained during its studies.
MMS requires (appropriately) that samples be competently identified and that voucher specimens be maintained. It is critical for determining whether change has occurred that all specimens be available for inspection. Indeed, frozen tissue samples from selected animals also offer extremely important reference information for assessment of future impacts of OCS activities. In order to provide taxonomic continuity for future MMS-supported research, MMS should support the systematists that made the benthic programs possible, and especially should support the extremely important long-term curatorship of archived samples. The marine mammal tissue bank being developed by NMFS (to which MMS contributes) could usefully be expanded to include birds and fish.